The diagnosis of central nervous system infection remains challenging for physicians because (i) community meningitis is still associated with high mortality rate and morbidity, and (ii) the diagnosis in context of intracranial injury and procedure is very difficult.
For the community meningitis, positive diagnosis is an emergency for starting antibiotherapy, especially in bacterial meningitis as Streptococcus pneumoniae, Neisseria meningitis or Hemophilus influenzae. 
For post injury or postoperative meningitis, clinical outcome is generally favourable, and treatment less emergent. Nevertheless, the clinicians have to differentiate infected from aseptic meningitis (Ross et al., 1988) and the difficulties of diagnosis result in the wide use of large spectrum antibiotics before confirmation of infection or not (Working Party of the British Society for Antimicrobial Chemotherapy, 2000). This favours iatrogenic over-selection of resistant organisms (Zarrouk et al., 2007). Micro-organisms implicated in such nosocomial meningitis relate to the large spectrum of bacteria in the patient's colonisation, especially Staphylococcus, (aureus or coagulase negative), enterobacteria and Pseudomonas. 
In both contexts, a rapid, specific, sensitive test for diagnosis of CSF infection is needed for helping therapeutic decision-making in clinical practice because:
1) symptoms and clinical presentation could be mild and non specific (fever, confusion, leukocytosis), sometimes masked by corticoids or therapeutic hypothermia (trauma or neurosurgical context),
2) classical meningitis criteria of cerebro-spinal fluid (CSF) analysis (pleiocytosis with high proportion of polymorphonuclear neutrophils (PMNs), low glucose and high protein level) are difficult to interpret if recent bleeding or recent surgical procedure,
3) direct bacteriological examination results may be negative especially when on-going antibiotic therapy for other infection is continued (Druel et al., 1996).
PMNs in cerebrospinal fluid (CSF) are the first line of defence in innate immune response to bacterial infection, and their phenotype may constitute the hallmark of infection (Tavares et al., 2006). One component of the killing system of PMNs is the radical oxygen species (ROS) production, also called respiratory burst (Segal, 2005). In this function, the NADPH oxidase plays a pivotal role by pumping superoxide ion (O2.) into phagocytic vacuoles. Superoxide production and its reaction products are collectively referred to as ROS (for radical oxygen species or reactive oxygen species, since both terms are used in the literature). They can be detected and measured by luminescence, fluorescence or colorimetry after oxidation of reactive components (Freitas et al., 2009).